GolamMostafa:
This is a Keypad-LCD-EEPROM based academic project in which a 10-digit code (consisting of any combination of 0, 1, ..., 9) is entered. After the entry, # key will store the code in EEPROM; b key will bring back the code from EEPOM and will show on LCD; * key will delete the code from buffer and EEPROM.
Fig-1: Hardware Block Diagram
Fig-2: Flow hart for the Control Program:Simple C Codes for Fig-2: (Tested and found working except filtering out of *, #, a, b, c, d from being printed)
#include<EEPROM.h>
#include<Keypad.h>
#include<LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
const byte rows = 4, cols = 4;
char storage[11]; //including space for null-byte
char storageB[11];
int adr = 0x0010;
int arrayTracker = 0;
byte flag11 = 0x00;
byte flag2 = 0x00;
byte flag3 = 0x00;
char input;
char keys[rows][cols] = {
{'1','2','3','a'},
{'4','5','6','b'},
{'7','8','9','c'},
{'*','0','#','d'}
};
byte rPins[rows] = {9,8,7,6}, cPins[cols] = {5,4,3,2};
Keypad keypad = Keypad(makeKeymap(keys),rPins,cPins,rows,cols);
void setup()
{
lcd.init();
lcd.backlight();
lcd.print("Enter 10-digit..");
lcd.setCursor(0,1);
}
void loop()
{
L0: input = keypad.getKey(); //L0:
if(input)
{ //L1:
if(flag2==0x00) //L1:
{ //L2:
if(flag11==0x00)//L2:
{//L3:
filterDigit(); //L3: do not print *, #, a, b, c, d
lcd.write(input); //show digit on LCD
storage[arrayTracker] = input; //save digit
if(arrayTracker == 9) //L4
{//L5:
arrayTracker++; //L5
storage[arrayTracker] = 0x00; //null-byte
flag11 = 0x01;
goto L0;
}
else
{ //L5A:
arrayTracker++; //L5A:
goto L0;
}
}
else
{ //L3A:
if(input == '#') //to save in EEPROM
{ //L3Y:
EEPROM.put(adr, storage); //save 10-digit code in EEPROM
delay(1000);
lcd.setCursor(0, 1);
lcd.print("Saved in EEPROM");
flag2 = 0x01;
goto L0; //L3Y:
}
}
//----------L3 : if-else--------------------
}
else
{
if(input == '*') //L2A:
{ //3X:
//delete code from array and EEPROM
for(int i=0; i<11; i++)
{
storage[i] = 0x00;
storageB[i] = 0x00;
}
EEPROM.put(adr, storage); //all digits are 0s
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Codes Deleted!");
lcd.setCursor(0, 1);
EEPROM.get(adr, storageB);
lcd.print(storageB);
flag3 = 0x01;
goto L0;
}
else
{ //L3XA:
if(flag3 == 0x00)
{ //L4X:
if(input == 'b')
{//L5X:
//read from EEPROM and show on LCD
EEPROM.get(adr, storageB);
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Code from EEPROM");
lcd.setCursor(0, 1);
lcd.print(storageB);
}
}
}
}
}
}
void filterDigit()
{
}
Have you written any code using 'State Machine' techniques?
Or code that has functions other than setup() or loop()?
Do you know what a flag is and how it can be used to control code execution?
Have you ever used switch/case.